The evolution of virtualization techniques has coincided, and to some extent has merged, with the movement toward cloud computing. In general, virtualization obscures hardware characteristics of a computing platform and instead presents an abstract platform that can host other platforms, including complete operating systems. One popular virtualization technique is to deploy a hypervisor (also known as a virtual machine manager) that can allow guest software (including complete operating systems) to run concurrently on an abstract host platform. The hypervisor can provide a simulated computing environment, often referred to as a “virtual machine,” for its guest software. Thus, multiple disparate operating systems can run under a hypervisor on a single physical machine, for example.
Cloud computing is generally the use of computing resources that are delivered as a service over a network, such as the Internet. In cloud computing, various remote computers, servers, and data storage systems can provide services by storing data and hosting applications. End user computers can access applications in the cloud infrastructure via a web browser or other application that provides network access to a host. Typically, compute, storage, and network resources are offered in a cloud infrastructure, effectively shifting the workload from a local network to the cloud network.
Virtualization applied to a cloud infrastructure can provide numerous benefits. In particular, a virtualized cloud infrastructure can maximize the output of the physical machines in the infrastructure, can enable customers to buy only the resources it uses or wants, and can provide flexibility and speed in responding to changes in a customer's network resource requirements. Virtual machines, however, are likely to become more popular targets for malicious attacks, as the use of virtualized cloud infrastructures continues to grow. While cloud virtualization provides many advantages, it can also present unique security challenges, as the nature of the virtualized infrastructure is to enable quick deployment of new resources. Hence, many challenges remain for providing a secure virtualized cloud infrastructure.